/*
 * This file is part of JaTeCS.
 *
 * JaTeCS is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * JaTeCS is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with JaTeCS.  If not, see <http://www.gnu.org/licenses/>.
 *
 * The software has been mainly developed by (in alphabetical order):
 * - Andrea Esuli (andrea.esuli@isti.cnr.it)
 * - Tiziano Fagni (tiziano.fagni@isti.cnr.it)
 * - Alejandro Moreo Fernández (alejandro.moreo@isti.cnr.it)
 * Other past contributors were:
 * - Giacomo Berardi (giacomo.berardi@isti.cnr.it)
 */

package it.cnr.jatecs.clustering.kmeans;

import it.cnr.jatecs.clustering.DocumentCentroid;
import it.cnr.jatecs.indexes.DB.interfaces.IIndex;
import it.cnr.jatecs.utils.iterators.interfaces.IIntIterator;

public interface IDocumentConvergeCriterion {

    /**
     * Start a new evaluation phase.
     *
     * @param documents The documents to consider.
     * @param index     The index object.
     */
    public void beginEvaluation(IIntIterator documents, IIndex index);


    /**
     * Indicate if the algorithm has been converged or if it is necessary to do more iterations. The documents
     * and index that will be considered are those specified in beginEvaluation() method.
     *
     * @param centroids The centroids of clusters.
     * @return True if the algorithm has been converged, false otherwise.
     */
    public boolean isConverging(DocumentCentroid[] centroids);

}
